[opus] [PATCH] Add Functions to Create Ambisonic Multistream Encoder
Michael Graczyk
mgraczyk at google.com
Mon May 23 17:27:27 UTC 2016
Hi Jean-Marc,
On Sat, May 21, 2016 at 1:58 PM, Jean-Marc Valin <jmvalin at jmvalin.ca> wrote:
> 1) I think "allocation mode" should be renamed to "mapping type" or
> something similar that to make it less confusing.
Done
> 2) After discussing with Tim, the conclusion is that we should use
> mapping family 254 in the short term. We can switch to mapping family 2
> when standardization is a bit more advanced.
Sounds good, done.
> 3) Unless it causes problems in the existing code, it seems like family
> 254 should already set mapping_type=MAPPING_TYPE_AMBISONICS. From my
> understanding, it would not change the code behaviour, but would make it
> clearer what the new type is for (or did I miss something?).
Done, I think. The patch still doesn't change behavior, but it now
sets the member OpusMSEncoder.mapping_type to MAPPING_TYPE_AMBISONICS.
-------------- next part --------------
From 75b9f240aabcc6418514831270af1ced5b11af77 Mon Sep 17 00:00:00 2001
From: Michael Graczyk <michael at mgraczyk.com>
Date: Mon, 2 May 2016 21:42:18 -0700
Subject: [PATCH] Add experimental support for ambisonic encoding
The implementation currently only codes each channel independently with no
special allocation rules.
---
configure.ac | 11 +++++++++
src/opus_multistream_encoder.c | 56 ++++++++++++++++++++++++++++--------------
2 files changed, 49 insertions(+), 18 deletions(-)
diff --git a/configure.ac b/configure.ac
index a67aa37..b6ca573 100644
--- a/configure.ac
+++ b/configure.ac
@@ -736,6 +736,16 @@ AS_IF([test "$enable_fuzzing" = "yes"], [
AC_DEFINE([FUZZING], [1], [Fuzzing])
])
+AC_ARG_ENABLE([ambisonics],
+ [AS_HELP_STRING([--enable-ambisonics],[enable experimental ambisonic encoding and decoding support])],,
+ [enable_ambisonics=no])
+
+AS_IF([test "$enable_ambisonics" = "yes"], [
+ AC_DEFINE([ENABLE_EXPERIMENTAL_AMBISONICS], [1], [Ambisonics Support])
+], [
+ AC_DEFINE([ENABLE_EXPERIMENTAL_AMBISONICS], [0], [Ambisonics Support])
+])
+
AC_ARG_ENABLE([doc],
[AS_HELP_STRING([--disable-doc], [Do not build API documentation])],,
[enable_doc=yes])
@@ -820,6 +830,7 @@ AC_MSG_NOTICE([
Custom modes: .................. ${enable_custom_modes}
Assertion checking: ............ ${enable_assertions}
Fuzzing: ....................... ${enable_fuzzing}
+ Ambisonics support: .............${enable_ambisonics}
API documentation: ............. ${enable_doc}
Extra programs: ................ ${enable_extra_programs}
diff --git a/src/opus_multistream_encoder.c b/src/opus_multistream_encoder.c
index 9e85773..3061373 100644
--- a/src/opus_multistream_encoder.c
+++ b/src/opus_multistream_encoder.c
@@ -70,13 +70,19 @@ typedef void (*opus_copy_channel_in_func)(
int frame_size
);
+typedef enum {
+ MAPPING_TYPE_NONE = 0,
+ MAPPING_TYPE_SURROUND = 1,
+ MAPPING_TYPE_AMBISONICS = 254,
+} MappingType;
+
struct OpusMSEncoder {
ChannelLayout layout;
int arch;
int lfe_stream;
int application;
int variable_duration;
- int surround;
+ MappingType mapping_type;
opus_int32 bitrate_bps;
float subframe_mem[3];
/* Encoder states go here */
@@ -242,6 +248,7 @@ void surround_analysis(const CELTMode *celt_mode, const void *pcm, opus_val16 *b
upsample = resampling_factor(rate);
frame_size = len*upsample;
+ /* LM = log2(frame_size / 120) */
for (LM=0;LM<celt_mode->maxLM;LM++)
if (celt_mode->shortMdctSize<<LM==frame_size)
break;
@@ -394,7 +401,8 @@ opus_int32 opus_multistream_surround_encoder_get_size(int channels, int mapping_
{
nb_streams=vorbis_mappings[channels-1].nb_streams;
nb_coupled_streams=vorbis_mappings[channels-1].nb_coupled_streams;
- } else if (mapping_family==255)
+ } else if (mapping_family==255
+ || (mapping_family==254 && ENABLE_EXPERIMENTAL_AMBISONICS))
{
nb_streams=channels;
nb_coupled_streams=0;
@@ -408,7 +416,6 @@ opus_int32 opus_multistream_surround_encoder_get_size(int channels, int mapping_
return size;
}
-
static int opus_multistream_encoder_init_impl(
OpusMSEncoder *st,
opus_int32 Fs,
@@ -417,7 +424,7 @@ static int opus_multistream_encoder_init_impl(
int coupled_streams,
const unsigned char *mapping,
int application,
- int surround
+ MappingType mapping_type
)
{
int coupled_size;
@@ -434,7 +441,7 @@ static int opus_multistream_encoder_init_impl(
st->layout.nb_streams = streams;
st->layout.nb_coupled_streams = coupled_streams;
st->subframe_mem[0]=st->subframe_mem[1]=st->subframe_mem[2]=0;
- if (!surround)
+ if (mapping_type != MAPPING_TYPE_SURROUND)
st->lfe_stream = -1;
st->bitrate_bps = OPUS_AUTO;
st->application = application;
@@ -463,12 +470,12 @@ static int opus_multistream_encoder_init_impl(
if(ret!=OPUS_OK)return ret;
ptr += align(mono_size);
}
- if (surround)
+ if (mapping_type == MAPPING_TYPE_SURROUND)
{
OPUS_CLEAR(ms_get_preemph_mem(st), channels);
OPUS_CLEAR(ms_get_window_mem(st), channels*120);
}
- st->surround = surround;
+ st->mapping_type = mapping_type;
return OPUS_OK;
}
@@ -482,7 +489,9 @@ int opus_multistream_encoder_init(
int application
)
{
- return opus_multistream_encoder_init_impl(st, Fs, channels, streams, coupled_streams, mapping, application, 0);
+ return opus_multistream_encoder_init_impl(st, Fs, channels, streams,
+ coupled_streams, mapping,
+ application, MAPPING_TYPE_NONE);
}
int opus_multistream_surround_encoder_init(
@@ -496,6 +505,7 @@ int opus_multistream_surround_encoder_init(
int application
)
{
+ int mapping_type;
if ((channels>255) || (channels<1))
return OPUS_BAD_ARG;
st->lfe_stream = -1;
@@ -523,7 +533,8 @@ int opus_multistream_surround_encoder_init(
mapping[i] = vorbis_mappings[channels-1].mapping[i];
if (channels>=6)
st->lfe_stream = *streams-1;
- } else if (mapping_family==255)
+ } else if (mapping_family==255
+ || (mapping_family==254 && ENABLE_EXPERIMENTAL_AMBISONICS))
{
int i;
*streams=channels;
@@ -532,8 +543,17 @@ int opus_multistream_surround_encoder_init(
mapping[i] = i;
} else
return OPUS_UNIMPLEMENTED;
- return opus_multistream_encoder_init_impl(st, Fs, channels, *streams, *coupled_streams,
- mapping, application, channels>2&&mapping_family==1);
+
+ if (channels>2 && mapping_family==1) {
+ mapping_type = MAPPING_TYPE_SURROUND;
+ } else if (mapping_family==254 && ENABLE_EXPERIMENTAL_AMBISONICS) {
+ mapping_type = MAPPING_TYPE_AMBISONICS;
+ } else {
+ mapping_type = MAPPING_TYPE_NONE;
+ }
+ return opus_multistream_encoder_init_impl(st, Fs, channels, *streams,
+ *coupled_streams, mapping,
+ application, mapping_type);
}
OpusMSEncoder *opus_multistream_encoder_create(
@@ -730,7 +750,7 @@ static int opus_multistream_encode_native
opus_int32 smallest_packet;
ALLOC_STACK;
- if (st->surround)
+ if (st->mapping_type == MAPPING_TYPE_SURROUND)
{
preemph_mem = ms_get_preemph_mem(st);
mem = ms_get_window_mem(st);
@@ -784,7 +804,7 @@ static int opus_multistream_encode_native
mono_size = opus_encoder_get_size(1);
ALLOC(bandSMR, 21*st->layout.nb_channels, opus_val16);
- if (st->surround)
+ if (st->mapping_type == MAPPING_TYPE_SURROUND)
{
surround_analysis(celt_mode, pcm, bandSMR, mem, preemph_mem, frame_size, 120, st->layout.nb_channels, Fs, copy_channel_in, st->arch);
}
@@ -813,7 +833,7 @@ static int opus_multistream_encode_native
else
ptr += align(mono_size);
opus_encoder_ctl(enc, OPUS_SET_BITRATE(bitrates[s]));
- if (st->surround)
+ if (st->mapping_type == MAPPING_TYPE_SURROUND)
{
opus_int32 equiv_rate;
equiv_rate = st->bitrate_bps;
@@ -859,7 +879,7 @@ static int opus_multistream_encode_native
(*copy_channel_in)(buf+1, 2,
pcm, st->layout.nb_channels, right, frame_size);
ptr += align(coupled_size);
- if (st->surround)
+ if (st->mapping_type == MAPPING_TYPE_SURROUND)
{
for (i=0;i<21;i++)
{
@@ -875,7 +895,7 @@ static int opus_multistream_encode_native
(*copy_channel_in)(buf, 1,
pcm, st->layout.nb_channels, chan, frame_size);
ptr += align(mono_size);
- if (st->surround)
+ if (st->mapping_type == MAPPING_TYPE_SURROUND)
{
for (i=0;i<21;i++)
bandLogE[i] = bandSMR[21*chan+i];
@@ -883,7 +903,7 @@ static int opus_multistream_encode_native
c1 = chan;
c2 = -1;
}
- if (st->surround)
+ if (st->mapping_type == MAPPING_TYPE_SURROUND)
opus_encoder_ctl(enc, OPUS_SET_ENERGY_MASK(bandLogE));
/* number of bytes left (+Toc) */
curr_max = max_data_bytes - tot_size;
@@ -1183,7 +1203,7 @@ int opus_multistream_encoder_ctl(OpusMSEncoder *st, int request, ...)
{
int s;
st->subframe_mem[0] = st->subframe_mem[1] = st->subframe_mem[2] = 0;
- if (st->surround)
+ if (st->mapping_type == MAPPING_TYPE_SURROUND)
{
OPUS_CLEAR(ms_get_preemph_mem(st), st->layout.nb_channels);
OPUS_CLEAR(ms_get_window_mem(st), st->layout.nb_channels*120);
--
2.8.0.rc3.226.g39d4020
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